Investigation finding that identifies the event, or combination of events and conditions, that most likely led to an occurrence.
What it is
The term is most closely associated with the US NTSB, which sets out in the conclusions of each report a probable cause statement followed by any contributing factors. Other authorities, following ICAO Annex 13 terminology, prefer ‘causes and contributing factors’. The word ‘probable’ is deliberate: the investigation reaches the explanation best supported by the evidence, not a courtroom certainty.
Modern investigations rarely find a single cause. Many draw on the so-called Swiss cheese model developed by the British psychologist James Reason: an occurrence happens when weaknesses in several successive barriers, such as design, maintenance, training, procedures or organisation, happen to line up. That is why reports look beyond the last link in the chain and ask why the defences failed.
Determining a probable cause is not the same as assigning blame. Its purpose is to steer the recommendations: if a confusing flight deck indication played a part, the fix lies in redesigning that indication, not simply in asking crews to pay more attention.
On Vuelopedia
Related terms
Cite
To cite this page in academic work, an article or Wikipedia, choose the style and copy the reference. The access date is today.
This page was last updated on October 9, 2026
APA
Vuelopedia. (2026, October 9). Probable cause. Retrieved October 16, 2026, from https://vuelopedia.org/en/glossary/probable-cause
MLA
“Probable cause.” Vuelopedia, Fundación Poderia, 9 Oct. 2026, vuelopedia.org/en/glossary/probable-cause. Accessed 16 Oct. 2026.
Chicago
Vuelopedia. “Probable cause.” Fundación Poderia. Last modified October 9, 2026. https://vuelopedia.org/en/glossary/probable-cause.
Harvard
Vuelopedia (2026) Probable cause. Available at: https://vuelopedia.org/en/glossary/probable-cause (Accessed: 16 October 2026).
BibTeX
@misc{vuelopedia_en_glossary_probable_cause,
author = {{Vuelopedia}},
title = {{Probable cause}},
publisher = {Fundación Poderia},
year = {2026},
date = {2026-10-09},
url = {https://vuelopedia.org/en/glossary/probable-cause},
howpublished = {\url{https://vuelopedia.org/en/glossary/probable-cause}},
urldate = {2026-10-16},
note = {Accessed 2026-10-16}
}Wikipedia
{{cite web |url=https://vuelopedia.org/en/glossary/probable-cause |title=Probable cause |website=Vuelopedia |publisher=Fundación Poderia |date=2026-10-09 |access-date=2026-10-16 |language=en}}